If reports are true that Chelsea Clinton and her boyfriend Marc Mezvinsky are considering marriage, the father of the groom won’t be able to attend the wedding until he is released from prison in November 2008. Ed Mezvinsky, a former Democratic Congressman from Iowa, is serving a seven-year sentence for fraud after getting caught up in a series of Nigerian e-mail scams. Initially, Mezvinsky became the victim of "just about every different kind of African-based scam we’ve ever seen," federal prosecutor Bob Zauzmer told 20/20 for a report to be broadcast this evening. THE BLOTTER RECOMMENDS Video The Secret Behind the ‘Black Money’ Scam Churches, Ministers Targeted by Nigerian E-mail Scammers Click Here to Check Out the Brian Ross Investigates Webcast: On the Trail of the Nigerian Scammers But then, says Zauzmer, Mezvinsky began to steal from clients and even his own mother-in-law to raise the money to try yet another scheme. "He was always looking for the home run. He was always trying to find the business deal that would make him as wealthy as all the people in his social circle," said Zauzmer. Click Here for the Brian Ross Investigative Homepage. After leaving Congress, Mezvinsky moved to Philadelphia’s Main Line suburbs with his wife Marjorie Margolies, a former television reporter, who won a seat in Congress herself as a Democratic congresswomen from Pennsylvania. "They were seen as people of means; they were a legitimate power couple," said Gar Joseph, a political columnist for the Philadelphia Daily News. The Mezvinkskys were also close to Bill and Hillary Clinton and were frequent guests at White House state dinners. Prosecutors say Mezvinsky used his connections to the Clintons and his son’s social relationship with Chelsea to persuade people to give him money to participate in the scams. Mezvinsky traveled to Nigeria numerous times and ultimately lost more than $3 million as a victim of the scammers. Prosecutors say Mezvinsky fell particularly hard for what is known as the "black money" scam. Victims are told millions of dollars have been coated with black ink so the money could be smuggled out of Nigeria. Click here to see undercover video of the "black money" scam. The scammers then offer to sell a special, expensive chemical to remove the black ink so the currency can be used. Prosecutors say Mezvinsky fell for at least three separate "black money" schemes that he thought would bring him millions. Mezvinsky declined requests sent to him in prison to speak with ABC News and also instructed his lawyer not to speak with ABC News. His wife, Marjorie Margolies, declined to comment "in the interest of the children." There is no evidence the Clintons knew of any illegal activity.